With a rapid development of electronic and communications technologies, a use of unit circuits having various functions and densely arranged in a narrow space has been technically possible. However, generation of electromagnetic interference (EMI) has been a problem; for example, a device malfunctions due to interference of electromagnetic waves generated between adjacent circuits by each circuit.
Electromagnetic wave shielding methods according to related arts may generally include sealing a circuit generating electromagnetic waves by using a shield can, coating conductive silicon along a joint and a connection portion of a circuit sectioning member formed in an electronic device to prevent leakage of electromagnetic waves through the joint and the connection portion, and sealing each circuit section by using a conductive shielding tape manufactured to have the same shape as a section line in a circuit.
Using a shield can is the most popular one among the above-described methods. According to the method using a shield can, electromagnetic waves generated in a circuit device may be blocked by covering an upper portion of the circuit device with a shield can that is manufactured in a can shape using a metal plate or plastic to which a conductive metal such as Fe, Cu, Ni, etc. is added.
For example, as illustrated in FIG. 1, a shield can S may include a lid L and a frame F assembled to the inside of the lid L. According to a related art, the lid L and the frame F are separately formed by press and then manually assembled or input to a separate assembly device to be assembled in one body. Accordingly, productivity is low compared to high manufacturing costs.
To address the matter, as illustrated in FIGS. 2 to 4, Korean Patent No. 10-0456126 discloses an apparatus that includes a material supply portion 100, a sensing guide portion 200, an assembly portion 300, a transfer portion 400, a scrap cutting portion 1 500, a finished product cutting portion 600, and a scrap cutting portion 2 700, thereby enabling automation of a manufacturing process of the shield can S.
In the method of manufacturing the shield can S, the lid L having a certain shape and a downwardly bent edge, and the frame adequately inserted into the inside of the lid L and having a contact portion F1 provided along the edge. A first-tier flat band 10, on which the lids L are continuously and repeatedly press-formed in a lengthwise direction thereof, is supplied in an upper side, and simultaneously, a second-tier flat band 20, on which the frames F are continuously and repeatedly press-formed in the lengthwise direction thereof, is supplied in a lower side. In this state, the frame F is punched to be inserted into the lid L formed on the first-tier flat band 10 while cutting support ends 21 of the frame F formed on the second-tier flat band 20. Then, support ends 11 of the lid L formed on the first-tier flat band 10 are cut so that the shield can S may be finished.
The above apparatus and method of manufacturing a shield for IC device has a merit of enabling automation of a shield can manufacturing process and thus reducing a defect rate.
Recently, stronger electromagnetic waves are generated as performance of electronic devices such as mobile phones is further improved. In order to improve shield performance with respect to the electromagnetic waves, a process of attaching a separate shielding tape to a surface of the shield can S is needed.
In this case, when the flat bands 10 and 20 wound in a roll shape are manufactured by a method such as extrusion, oil and so forth from a mold may coat surfaces of the flat bands 10 and 20 so that an adhesion force of a shielding tape is deteriorated.
Furthermore, in a state in which oil is coated on the surfaces of the flat bands 10 and 20, when the shield can S is manufactured and applied to mobile phones, performance of the shield can S is deteriorated due to radiated heat of electronic parts so that the interior of an electronic product is contaminated.